Puya raimondii is rivalled only by members of the Ceroxylon
palm genus as the most spectacular high-Andean plant. It occurs in often
very isolated and usually small populations or rodales from Peru
to Bolivia. Communities
frequently number a few hundred individuals or less, but can range up to perhaps 30,000 plants in Paso Winchus as well as in Cashapampa, Pachacoto and
sector Carpa, Huascarán National Park, Huaraz, which is probably Peru’s best
known location. Populations reach 10,000 in Rodeo, Arani
province, Bolivia’s
largest population which may represent one third that country’s plants. In Titankayoc in southern Peru’s Ayacucho,
however, there is an extraordinary site of several thousand hectares which
contains, depending on source, an estimated 250,000 to at least 450,000 plants.
With this arguable anomaly, the plant’s sporadic and scattered distribution and
extreme genetic homogeneity, detailed below, suggest the vestigial remains of a
species in decline. Outside its habitat,
there appear to be no more than two dozen mainly small specimens in perhaps
half a dozen botanical gardens.

The plant is monocarpic and in
habitat seeds only once in about 80 years or more before dying. Although
a mature Puya will produce 8–12 million seeds
and viability is usually good, inclement montane conditions at the time of
dispersal, which may inter alia affect
pollinating insects, can result in few if any germinations. Moreover, seeds in less than ideal conditions can begin to lose germinating
ability after a few months and are also susceptible to damping-off.
Because of these factors, a century-old plant may not reproduce at all and
will, botanically, have lived in vain. This risk is exacerbated
by global warming whose effects on Peru’s glaciers are well established. Climate change may already be impairing Puya raimondii’s ability to flower (Venero pers. comm.).

In the wild, these plants seem to be exceedingly choosy about where they grow. Their seeds
are very small and by design easily wind-blown. Yet even in undisturbed
locations P. raimondii can limit itself
to one small spot although edafic, topographic and microclimatic conditions in
the surrounding area appear identical.

The species is officially considered
endangered in Peru
(Law No 043- 2006-AG). But in practical terms this means little, if
anything and only the country’s best-known rodales (Puya communities) benefit from some protection. Elsewhere, the plant can
be the object of hostility and large stones are often thrown at them, lodging
for years among the leaves. Cattle roam
unfettered among many colonies which are not being regenerated because the
animals either trample or may eat juveniles. In other sites, fires are
set to create pastureland or the thorny leaves are burnt to facilitate access
to the trunks' starch which becomes cattle fodder. Pith removal, of course, kills the plant.

Compounding all these issues,
there is exceedingly little genetic variety within existing populations. A
genomic DNA analysis (Sgorbati et al.) of the genetic structure of eight
populations (including the huge one at Titankayoc) representative of P. raimondii in Peru detected just 14 genotypes in
160 plants. Only a few of the 217 AFLP
marker loci screened were polymorphic and four populations were completely
monomorphic. Less than 4% of the total
genomic variation was within populations and genetic similarity among
populations was as high as 98.3%. Flow
cytometry of seed nuclear DNA content and RAPD marker segregation analysis of
progeny plantlets demonstrated that the extremely uniform genome of these
populations is not compatible with agamospermy but the result of inbreeding. Many rodales have
disappeared only recently, as proved by vernacular Puya names still in local use. Even though fully fitted to its
harsh environment, P. raimondii lacks
sufficient variability in its genome and, possibly also phenotype variability
to allow it to adapt to both anthropic pressure and present climate change.

This plantusually occurs at around 4,000 m in the Andes of Peru and Bolivia, but it ranges from 3,000 m up to 4,800 m (both extremes occur in Bolivia). Its communities are often very isolated from each other and can be found in pockets from Calipuy in northern Peru, Huaraz in the centre to Apurimac and Ayacucho in the south, crossing into western Bolivia’s La Paz province, Cochabamba in the centre and Potosí in the south. The most important site by far in Peru is Titankayoc - Chanchayoc in Ayacucho, while Bolivia’s largest known community is in Rodeo, Arani province. A single reference to Puya species in southern Ecuador and northern Chile has not been verified.

Thanks to a single enormous subpopulation, which could represent most of the world’s population of P. raimondii, the number of these plants in Peru may number 800,000 individuals. Bolivia is estimated to have 30,000-35,000 plants.

Typical habitat for this species occurs at about 4,000 m but can extend from 3,000–4,800 m. At these levels, air temperatures range from very cold (as low as -20ºC or less) to an estimated maxima of 8–24ºC. Precipitation, as rain, hail or snow falls mainly from October to March. The ground is almost invariably rocky and usually sloping and friable. Drainage requirements or an inability to compete with other flora in more fertile land may account for the rarity of P. raimondii in damp gullies although a few specimens have been seen close to standing water. Still less clear is why a plant known to thrive in very different ex-situ conditions confines itself to a single spot on a mountainside when surrounded by seemingly similar terrain; or why population densities can vary considerably among and within communities.

The Puya’s ability to grow and even thrive in quite different conditions (low altitude, high humidity, high temperature) in which maturity can be reached in half the time needed in the wild, makes the plant a candidate for a range of ex situ environments.

The Puya trunk’s pith is at least occasionally
harvested to feed domestic animals. Simple furniture is sometimes made from the plant and its woody parts
used for fuel. Leaves are buried upright
in the ground to form rudimentary fences in a few Bolivian villages and can
sometimes be inserted in the tops of stone walls to enhance separation in Peru where they
may also be used to shed rain from adobe walls. Such usages are strictly local and usually small-scale.

The Puya is susceptible to threatening events because its communities are generally small and very isolated from
each other. This has apparently rendered
populations extremely homogeneous genetically due probably to autogamous
inbreeding depression and so at greater risk to disease, parasites or predators
accompanying climatic change. The latter
is well documented and manifest in Peru’s rapidly receding glaciers. For possibly
related but as yet unknown reasons, at least one population has not flowered
for decades.

The major risk in most communities, however, is due to
human impact including repeated fires to generate or maintain pasture land and usage
as fuel or building material by local populations. An added incentive is the fear that Puyas may
‘capture’ grazing animals with their leaves’ (fearsome) inward-curving spines. This is probably very rare but not
inconceivable. Native birds have been
ensnared and killed this way.

Puyas are
officially considered endangered and protected by legislation in Peru (Law No 043- 2006-AG). But the practical enforcement of this measure
are not evident outside of one national park and the law must be strengthened
and enforced. Likewise, Peru’s pertinent authorities should be
urged to
promote Puya communities as a tourist attraction and to raise awareness of
the plant’s value among both children and adults living near existing groves.
Acción Ambiental plan to select at least one reserve for
specific conservation measures. This
may be the huge Titankayoc site or one nearer the major tourist destination, Cusco.

The plant also needs to be far
better known and steps should be taken to strengthen communities of P. raimondii genetically. To this end, we plan to collect seeds from
the most divergent Puya sites, altitudinally and latitudinally, to reproduce
in nurseries as a reserve. Following
further research and if endorsed by experts seeds might ultimately be used to
cross-seed (some) existing populations. Reproducing and extending the plant, which
in a sparse habitat has significant ecological importance, is another
priority. Establishing one or more new
rodales in promising sites will be
evaluated.

The
‘Queen of the Andes’ is also
of considerable ornamental value and introducing it as a dramatic landscaping
element internationally as well as nationally is another goal. The author is aware of only a few specimens
being used for such purposes in Peru’s
Puno and Cusco provinces. Preliminary contacts have already been
established with several foreign botanical gardens.